Loading ramp



April .3, 1951 I A. s. I-IAMILTQN, JR Y 2,547,460

LOADING RAMP ATTORNEY l April 3, 1951 A. s. HAMILTON, JR

LOADING RAMP 3 Sheets-Sheet 2 Filed March 8, 1950 I N VEN TOR ATTORNEY A. S. HAMILTON, JR

April 3, 1951 LOADING RAMP 3 Sheets-Sheet 3 Filed March 8, 1950 ATTORNEY Patented Apr. 3, 1951 UNITED STATES PATENT OFF-ICE 9 Claims.

.This invention relates to a-loading.1'amb,.more

,particularly-of, the...typ.e.that provdesarloor plate .connecting a loading dock .with the riool' or tail ,gate .ofa transport trucker trailerto .enable oper- Latnga power .or handy truokfrom .the loading .dock ontoV the, -floor of the. transport truck for wloading .or `unieadios .mechandise ,and `it nas for .its lpurpose .to afford .a .practical 4 and enicient 4structure .which can .be readily .controlled and l.renders the ,iioor plate of.' .the ramp self-adjustable. .to any angle .of ,inclination of the ,door of the. transporttruclr.

In the .usual operation of .loading .a transport truck .fromaloadng dook, theforward portion y.of .the ramnsrelevatedsothat the front edge of its floor plateis above .thelevelof thefloorofgthe .transport truck .which .is then .backed against .the loadingdock. .Thereupon the ramp is permitted to lower yuntil .the front .edge of theioor `platerests onV the .floor 4.ci the ltransport truck. .I ijhowever, the ground on which the transport truck lis restinglsnot Alevel or the Springs. kor tires .of .the truck arelower on one sidey .than .on the other, thei'loor of the Ytruck. is inclined'l'aterally and consequently the floor plate of theiloading .rampif v it moves downwardly to the sarneeXtent athroughout its wentire width will bein engagement with the, truck door at one point and above the truck floor at another point so that a wide gap.A existsbetweenoneportion of the floor plate of] the. ramp and the truck floor which `is likely to upset a hand truck and spill merchandise or .make .it difficult to .move a hand truck from the .loading dock onto the transport truck door or in .the opposite direction, and it is a. particular purpose of this invention `to afford a loading ramp so contructed that the 'forwardedge of the ioor plate of .the ramp or the forwardextension plateor lip which rests on the floor of the transport `truck adjusts itself automatically to the -angle of'inclination of the truck floor on which it rests and lies .in .close contact with the truck :OQr 'throughout the width of the ramp irrespective .of vthe angleat which the truck floor may be disposed.

vvIt is important that the licor plate of ;a loading ramp be flush Aat -its' rear end with `the loading dook in order thatloading trucks may readily move Vfronrthe dock onto the ramp, and if a 'floor vplate consists of a single sheet of1metal alined at its rear end with the dock surfaceand heavy enough to supporta loading truck without bending, the oor plate will not vadjust itself at its front edge to the vfloor of a transport truck when. the llatterzis inclined to a horizontal plane,

,2" andif the oor plate is of suniciently thin .metal to permit v.its .front edge to adjust itself to a horizontally inclined floor of a transport truck, it will not .be suliciently strong or stil to Vsuppport a loading truck without bending,4 `and itis apurposeof the invention to afford a construction in which afloorplate can bemadesuiciently heavy and stiff to support loading trucks and sufciently flexible to conform at its rear end kto the surface .of a loading Vdoel: while .its frontend adjusts itself to any angle` of inclination Aof .the transport truck floor o1' .tail gate ,and .the body of the floor plate can warp Vto,colrlpensat,for the different angles `of elevation l of Athe supporting bars.

Specifically the purpose of the invention is to afford a ramp in which the lforward portion of ,the Iioor of the ramp or the Yforwardmost plate extension follows .closely any .up or `down movement of the truck floor, one side ofthe .plate extension being permittedl to roccupy ,a position several inches lower than the .other sideso that there is never a drop or break between any portion of the forward edge of the ramp floor plate and the floor of the transport truck which might cause upsetting of a hand truck or injury .to the operator.

An additional object of .the invention ,is to afford a construction in which a oor plate rests on and is pivotally or interlockingly but loosely connected to a multiplicity of supporting, hars that are movable independently inparallel spaced vertical planes, so ,that the floor plate which extends across the supportingV bars Imay occupy a position inclined in two directions to a .hori- Vzontal planeV and conforming. .to any .inclined position of the transport truck floor, lwhile .the supporting bars on which .the door vplate is mounted can Yoccupy ,corresponding positions at different elevations and thus provide proper and adequate support for` the oor plate regardless of the inclination at Which it may belocated.

A further purpose of the invention is to 4afford a practical and eicient arrangement in which a plurality of supporting bars may be pivotally arranged Vat their rear ends for independent vervtical swinging movement and .a plurality ,of Vfloor plates can be arranged on the. supporting -bars extending thereacross and in juxtarelationship endwise, eachoor plate having a loose interu -locking or pivotal connection with .the supporting bars to permit the necessary vertical movement of the supporting bars and, the relative lateral movement of each licor plate as the .latter occupies `a'warpedV and inclined .position in contact with the inclined truck iioor and above the dierently elevated supporting bars.

An additional object of the invention is to afford a structure in which the floor plates are adecuately strengthened and braced and the supporting bars are mounted and connected in such manner as to insure their accurate movement in parallel planes while at the same time affording practical and efficient means for supporting at the forward edge of the ramp an extension plate which is preferably separate from and inclined slightly downwardly from the front edge of the forwardmost floor plate to facilitate movement of a hand truck from a loading dock onto the floor of a transport truck.

In a more particular aspect, the invention has for its purpose to provide a construction in which the floor of the ramp is made up of separate floor plates, each extending for a portion of the length of the ramp, the several floor plates being arranged in juxtarelation to each other endwise and extending across independently movable supporting bars that swing in vertical planes, and each oor plate being loosely interlocked with and movable laterally of the supporting bars so that the forward edge of the forwardmost iioor plate adjusts itself automatically to the floor of a transport truck when disposed at an angle to a horizontal plane while the rear edge of the rearmost oor plate is alined with the dock surface, and the intermediate floor plates are correspondingly warped and arranged on the supporting bars so that there is a continuous and unbroken floor or truck-supporting surface from the dock surface to the floor of the transport truck.

To these and other ends, the invention consists in the construction and arrangement of parts that will appear clearly from the following description when read in conjunction with the accompanying drawings, the novel features being pointed out in the claims following the specification.

In the drawings:

Fig. l is a plan view of a loading ramp constructed in accordance with a preferred embodiment of the invention;

Fig. 2 is a front elevation of the same showing the ramp and oor plates in normal position flush with the top surface of the loading dock;

Fig, 3 is a view in side elevation of the structure appearing in Fig. 1;

Fig. 4 is a transverse vertical sectional View on line 4 4 of Fig. 3 looking in the direction indicated;

Fig. 5 is a front elevation similar to Fig. 2 with parts omitted, and showing the iioor plates in the position which they occupy when inclined in two directions to a horizontal plane and warped to aline the extension plate with an inclined floor of a transport truck, the supporting bars being correspondingly positioned at different elevations;

Fig. 6 is an enlarged transverse vertical sectional View of the central supporting bars and central portion of a floor plate resting thereon, looking from the front end toward the back end Iof the ramp and illustrating the position of two supporting bars when the floor plate is in a position inclined in two directions to a horizontal plane as in Fig. 5;

Fig. 7 is an enlarged detail sectional view taken on line 1--1 of Fig. 1;

Fig. 8 is an enlarged detail sectional view taken on lme 8 8 of Fig. 2;

Fig. 9 is an enlarged detail sectional view taken on line 9 9 of Fig. 2;

Fig. 10 is an enlarged detail sectional View showing the connection between the fixed shaft on which the supporting bars are mounted and the bearing for one of the pivoted supporting bars, and

Fig. 11 is an enlarged detail sectional view showing the connection between the supporting bars and the elevating means.

Referring more particularly to the drawings in which like reference numerals refer to the same parts through the several views, I designates the top surface of the loading dock at the rear of the ramp while 2 designates the top surfaces of the loading dock at the sides of the ramp, see Figs. 3 and 4, 3 is the pit Within which the ramp is housed, and 4 designates the bottom of the pit upon which the supporting members are mounted, as will be described presently. l

The top or oor ofthe ramp comprises a plurality of rectangular floor plates which are independently supported in juxtarelation to each other and movable relatively to their supporting bars, and in the arrangement shown, there is provided a rear floor plate 5 which extends over the loading dock and a short distance forwardly over the supporting bars, an intermediate floor plate 6 with its rear edge in juxtarelation to the .floor plate 5, and a forward floor plate 'I with its rear edge in juxtarelation to the floor plate B. In advance of the iioor plate 1 and in juxtarelation thereto is an extension plate 8 which is preferably inclined downwardly from the forward floor plate 1 and is adapted to engage and adjust itself to the floor or tail gate of a transport truck, while the rear floor plate 5 occupies a position substantially flush with the rear dock surface I. The several iloor plates and extension plate preferably extend entirely across the supporting bars of the ramp, to be described presently, and rest on the supporting members, although it is to be understood that there maybe a greater or less number of floor plates as requirements demand. c*

Each iioor plate is preferably of steel from T35" to 1A thick, and extends across a plurality of supporting bars to which it is connected in such manner as to permit the iloor plate to warp and move slightly laterally of the supporting bars while the latter can swing in spaced parallel vertical planes, and to accomplish this objective, there are. provided a series of supporting channel bars 9, see Figs. 3 and 4, each of which has fastened thereto at its rear end a bearing or pillow block I0 that is rotatably mounted on a stationary shaft I I. The shaft II is xedly held in clamping blocks I2 by means of bolts i3 suitably anchored in the concrete base while I4 designate limit blocks positioned with their front edges in contact with the shaft I I and their rear edges abutting the rear wall I5 of the pit, and acting to hold the shaft I I in true alinementand to prevent bending or distortion of the shaft il in case of endwise pressure exerted against the .front ends of the supporting bars 9 when a transport truck is backed against the latter.

With this arrangement, each supporting channel bar 9 is movable on the fixedshaft I i by swinging about the latter in a vertical plane, the several supporting bars i) being spaced and arranged preferably as shown in Fig. Lhand. the supporting bars 9 which are secured to the pillow blocks l0 are so mounted on the shaft I I asto insure movement of each supporting bar in a true asumen vertical plane perpendicular to the axis or'shait I vi. withoutll'ikelihood of any s'idewise oritwisting motion. The supporting channel 'bars "9 `constitute a .rigid Aand 'firnisupport for the door plates of the ramp., irrespective of the `positions 1assuinediby the door plates, and in order tovenabl'e this objective, each floor .plate extends rentirely across the severalsupporting bars "9 andis con.- nected thereto by pivotal connections or interlockingmeans .that permitslight lateral play' and warping between the licor plate and the Supportinebars.

This is .accomplished preferably 'by .providing each door plate with. metal pins f6 rigidly .fastened tothe floor platelby welding` or in any suitable fashion and extending downwardly therefrom, see Figs. 4 vand 6', through openings .l1 provided in the top walls i8 .of the channel bars il.' The openings il are s ucienty larger than the ,pins E6 .to permit aslightlateralmovement and warping-ofthe door plate relatively to the. channelbars 9 so astoperrnit the supporting barsil .to occupy .positions .at different elevations while .accommodating themselves to any horizontally inclined or warped position'of the iloor .plates resting thereon, .as shownin Figs. 5 and "5. It will beunderstood that .theiloor platesmay'be loosely or .pivotally connected to the supporting bars .in .any suitable fashion `to perrn't .the supporting bars .to .assume positions .at .different elevations inv parallel vertical planes when the ldoor plates .are inclined .or warped to aline with a horizontally inclinedltruck floor or tailgate. In order to stifen .and strengthenadequately the oor plates, they are preferably provided with i spaced` parallel .channel bars or vangle bars i9, see Figs. .4 and, whichare welded or otherwise Arigidly fastened .at their edges .tothe undersurfaceof each floor plate .and extend .between 4aol-- jacent channel ,bars 9 transversely of .the door section. rIhese angle bars .i9 are .preferably 4about 8 apart, about .2. wide, and abou .'Tf"

thick.

Such a loading ramp ycan .be .made vin various sizes and they have .beenccnstructed successfully in three lengths e1- 5,.8 and 3.2.".respectively with door plates having .widthsof 6. or .6. 6." for the. 8S A.and `12 ramps, anda width of 550.1 6 forthe. 5 length ramps. vEach liloor .plate .extends vacross .the entire width of the ramp resting on the several supporting channel bars dandlengthwise-.of the ramp a .distance depending upony the .number .of floor plates that. are desirable to be employed, depending upon thelength of the ramp and the .particular character of work to be done. There may he three floor plates with. an extension plate .at .the front .end as shown, or `there may be a greater or less nnniber lof hoor Aplates..without.departing from the essential purposespfthe invention.

In order to connect .the supporting barst and .equalize their vertical .movements so as toinsure positioning in parallel vertical planesat .all elevations, they are connected at vtheir forward ends by equalizing devices in the` forni of parallel bars pivotally connected to the supporting bars, and to accomplish this each channel'bar 9 .has welded or otherwise fastened thereto at its iront 'end a web or plate H, seeFigs. 8 and 9, theplates 2! being preferably disposed at a slight angle to a plane perpendicular to the bottom wallZ of the channel bar il.y shown in Fig-8,A `fora*purpose that will'appear, presentlyl TheV bottom wall 2v2 ofthe channel barextends beyondV thetop wall' f' lf3, see Fig. '8, `which terminates ata point-coincident 6 withthe-front edge ofthe forwardmost floorplate T, the. central web and top wall of the `channel bar being cut-away on an incline, as shown -at2`4 for a purposethat will appear presently.

Pivotally mounted on the vseveral supporting plates 21 at the forward ends of the supporting bars 9 are the transverse parallel equalizing bars 25 and 25, these being held in pivotal relationship to the plates 2i by-means ofv the bolts 2E thus per- :fnittingthe channel bars 9 to assume positionsV at diierent. elevations, as shown inY Fig. 5, and the channel bars are maintained always in parallel relationshipas they-'move romtheposition shown in Fig. 2 tothat s lown in Fig. 5. 28 designatesa bumper rail secured in front of the Yparallel bars 25'and 26' and held in place by bolts'2-9connecting the bumper rail 29 with the platesI 2i.

The extension plate il previously referred to, and' shown in Figs. '1 and 3, is xedlycarried-by the upper equalizing bar 25 to which lit iswelded or otherwise attached-in perpendicularl relation as shown in Figsx ande, the extensionplatve-S-overlying and being in Contact withth'e inclined upper edges 24 of the supporting bars @and with its rear edge in juxtarelation to the front edge of the forwardmost oorV plate With this arrangement it will be seen that as the extension platef becomes inclined laterally'bycontactV with anfinclined floor ortail gate of a transport truck, the equalizing bars 25 and 2e assume correspondingly inclined positions and carry with them the several supporting channel bars on which the'loor plates rest so that the floorplates, which are loosely supported on the supporting bars but interlocked therewith, assume positions warpedand inclined to a horizontal planel as determined by the position of the extension plate 8, and the supportingchannel bars thus assume differently elevated positions corresponding to the degree of warpingandinclination of the iioor plates laterally.

In order to elevate the ramp, there is provided a fluid-pressure elevating means comprising a cyl inder 32', see Fig'. 3, connected by'pipe 3d with any suitable source of huid-pressure supplywhi-le 3Q designates a conventional valve control means for the fluid-pressme supply to elevate and permit 'lowering o'f a piston within the cylinder 32. The

piston in cylinder 32y is connected by a universal joint 35 to a cap 3S that is -Xedly mounted on a frame including two channel irons 3??, see Figs. `1 and 11, which span the two central supporting Abars 9, thevframe carrying the cap 36 beinfr loosely supported on the -two centralbars 9 by suitable connections 33 that permit the. fluid-pressure `mea-ns to elevate the ramp or perm-it. lowering the same while allowing for the variable movements Ior positions of thechannel supporting. bars when at different elevations. The fluid-pressure cylu inder 3.2 is mounted by means of a pivotal convnectionl), see Fig. 3, in a base il that is anchored "movement their-rear ends swing about .fixed 'shaft .1.13, and when 4they have reached a :suine s operated ciently high position so thatY the extension plate 8 will clear the oor of a transport truck, the transport truck is backed under the extension plate 8. When the transport truck is in loading position in relation to the loading dock, the fluid-pressure is released and the floor plates and supporting bars are permitted to lower until the front edge of extension plate 8 engages the iioor of the transport truck or the tail gate thereof, whichever is in operative position.y The extension plate S will then adjust itself to the floor of the truck and assume a position in close contact therewith throughout the width of the extension plate irrespective of the angle of inclination at which the truck iioor may be positioned at the moment. As the extension plate 8 assumes a position inclined to a horizontal plane, the transverse equalizing bars 25 and 26 assume correspondingly inclined positions and the supporting channel bars which are connected therewith occupy positions at varying elevation, as illustrated in Fig. 5. Consequently the floor plates 'l and 5 assume corresponding warped and horizontally inclined positions while retaining their interlocked relation with the supporting bars, and the rearmost floor plate T retains a position in contact with the rear ends of the supporting bars and in substantial alinement with the adjacent surface of the loading dock so that a continuous and uninterrupted floor surface is maintained from loading dock into the transport vehicle or truck, the several iioor plates being maintained at such relative inclination to a horizontal piane and so warped as to insure safe movement of a hand truck on to the floor of a transport vehicle without a break or drop from the front end of the extension plate onto the iioor of the truck.

While the invention has been described with reference to certain details of construction as herein shown, it is not confined to the particular arrangement disclosed and this application is intended to cover such modifications or departures as may come within the purposes of the improvements or the scope of the following claims.

I claim:

l. A loading ramp comprising a fixed shaft, a plurality of spaced supporting bars pivoted at one end on said shaft and independently movable in spaced parallel vertical planes, a floor plate extending across and resting on said supporting bars, and connectors on said 'floor plate loosely engaging portions of said supporting bars and having limited movement relative thereto pei'- mitting the floor plate to occupy a position inclined in two directions to a horizontal plane and the supporting bars to occupy positions at correspondingly different elevations.

2. A loading ramp comprising a fixed shaft, a plurality of spaced supporting 'oars pivotally mounted at one end on said shaft and independently movable in spaced parallel vertical planes, a floor plate extending across and resting on said supporting bars, and connectors on said floor plate loosely engaging enlarged openings in said supporting bars and having limited movement relative thereto whereby the floor plate is permitted slight lateral movement relatively to the supporting bars and can occupy a position inclined in two directions to a horizontal plane and the supporting bars can occupy positions at correspondingly different elevations.

3. A loading ramp comprising a fixed shaft, a plurality of spaced supporting bars pivoted at one end on said shaft and independently movable in spaced parallel vertical planes, a iioor plate extending across and resting on said supporting bars, and downwardly extending interlocking pins carried by the iioor plate and engaging openings in the supporting bars, said openings being somewhat larger than the interlocking pins and permitting lateral movement of the iioor plate relatively to the supporting bars when the latter occupy positions at different elevations and the iioor plate is inclined in two directions to a horizontal plane.

4. A loading ramp comprising a xed shaft, a plurality of spaced supporting bars pivoted at their rear ends on said shaft and independently movable in spaced parallel vertical planes, spaced transverse parallel bars connecting said supporting bars at their front ends, a plurality of floor plates extending across and resting on said supporting bars in juxtarelation to each other, and interlocking connections on each of said floor plates loosely engaging portions of the underlying supporting bars and having limited movement relative thereto permitting the oor plates to occupy positions inclined in two directions to a horizontal plane and the supporting bars to occupy positions at correspondingly different elevations.

5. A loading ramp comprising a fixed shaft, a plurality of spaced supporting bars pivoted at their rear ends on said shaft and independently movable in spaced parallel vertical planes, equalizing devices movably bolted to the supporting bars forwardly of said pivoted rear ends, a plurality of floor plates extending across and resting on said supporting bars in juxtarelation to each other, and interlocking connections on each of said floor plates loosely engaging portions of the underlying supporting bars permitting the floor plates to occupy positions inclined in two directions to a horizontal plane and the supporting bars to occupy positions at correspondingly different elevations.

6. A loading ramp comprising a fixed shaft, a plurality of spaced supporting bars pivotally mounted at their rear ends on said shaft and independently movable in spaced parallel vertical planes, a plurality of floor plates extending across and resting on said supporting bars in juxtarelation to each other, each of said floor plates having interlocking devices loosely engaging portions of the underlying supporting bars and having limited movement relative thereto permitting slight lateral movement of the iioor plates in relation to the supporting bars when the latter are located in diierent elevations and the floor plates are inclined in two directions to a horizontal plane, a transverse equalizing bar movably bolted to the supporting bars at their front ends, and an extension plate carried by said transverse bar and located adjacent to and in downwardly inclined relation to the forwardmost floor plate.

7. A loading ramp comprising a fixed shaft, a plurality of spaced supporting bars pivoted at their rear ends on said shaft and independently movable in spaced parallel vertical planes, a plurality of floor plates extending across and resting on said supporting bars in juxtarelaton to each other, each of said iioor plates having downwardly extending interlocking pins fixedly carried thereby and engaging openings in the supporting bars, said openings being somewhat larger than the interlocking pins and permitting slight lateral movement of the floor plates relatively to the supporting bars when the latter occupy positions at different elevations and the floor plates are inclined in two directions to a.

horizontal plane, transversely arranged plates fixed to'fthe supporting bars at their forward ends, transversely extending spaced parallel equalizing bars movably bolted to said transverse plates and connecting said supporting bars, and an extension plate xedly attached to the upper of said equalizing bars and located adjacent to and inclined downwardly from the forwardmost oor plate.

8. A loading ramp comprising a fixed shaft, a plurality of spaced supportingv bars pivoted at their rear ends on said shaft and independently movable in spaced parallel vertical planes, a plurality of licor plates extending across and resting on said supporting bars A in juxtarelation to each other, spaced parallel angle bars rigidly attachedA to the underside of each floor plate between `said supporting bars, each of said oor platesihaving fixed downwardly extending interlocking pins engaging openings inthe supporting bars, said openings being somewhat larger than the interlocking pins and permitting slight lateral movement of the floor plates relatively to the supporting bars when the latter occupy positions at diierent elevations and the floor plates are inclined in two directions to a horizontal plane, an extension plate movably bolted to the supporting bars at their forward ends and located in juxtarelation and downwardly inclined to the forwardmost floor plate, and elevating means associated with the supporting bars.

r9.` A loading ramp comprising ajxed shaft, a plurality of supporting bars pivotally mounted at their rear ends lon said shaft and independently movable in spaced vertical planes; a plurality of oor plates extending across and resting on said supporting bars in juxtarelatin to each other, said iioor plates having downwardly extending interlocking pins carried thereby engaging openings in the supporting bars, said openings being somewhat larger than the interlocking pins permitting slight lateral movement of the floor plates relatively to the supporting bars when the latter occupy positions at different elevations and the oor plates are inclined in two directions to a horizontal plane, an equalizer bar movably bolted to the forward ends of the supporting bars, and an extensionplate carried by said equalizer bar and located fin juxtarelation and downwardly inclined to the forwardmost floor plate.

ARTHUR S. HAMILTON, JR.

REFERENCES CITED The following references areof record in the le of this patent:

UNITED STATES PATENTS Number Name Date 408,805 Kent et al Aug. 13, 1889 807,231 Alsop Dec. 12, 1905 1,112,543 Love Oct. 6, 1914 

